Field of the Invention
The invention relates to a device for driving at least one capacitive actuator, in particular a piezoelectrically operated fuel injection valve of an internal combustion engine. The invention also relates to a method for operating the device.
Published European Patent Application EP 0 464 443 A1 discloses a piezoelectric actuator which is charged from a capacitor via a charging coil. During discharging of the piezoelectric actuator, part of the energy applied is fed back into the capacitor via a discharging coil, while the other part is converted into heat, likewise via the discharging coil. During discharging, a negative voltage is present across the piezoelectric actuator. German Patent DE 36 21 541 C2 discloses a driver circuit for a piezoelectric actuator of a fuel injection valve which is charged via a series circuit, connected to a voltage source and composed of two capacitors, and a charging coil, and is discharged into one of the two capacitors via a discharging coil. In an alternative configuration, the actuator is charged via a capacitor, connected to a voltage source, and a charging coil; during discharging, the energy stored in the piezoelectric actuator is destroyed by a discharging coil.